Hermetic sealing is important for many microfabricated devices and/or components requiring contamination-free surfaces in order to operate as intended. Examples of such devices include surface acoustic wave (SAW) filters and other types of acoustic devices as described, for example, in U.S. Pat. No. 4,162,465, entitled "Surface Acoustic Wave Device With Reflection Suppression", by B. J. Hunsinger and K. Hanma, acoustic charge transport (ACT) devices as described in U.S. Pat. No. 4,633,285, entitled "Acoustic Charge Transport Device and Method", by B. J. Hunsinger and M. J. Hoskins, heterostructure ACT devices as described, by way of example, in U.S. Pat. No. 4,893,161, entitled "Quantum-Well Acoustic Charge Transport Device" by W. J. Tanski et al., integrated optical components as described in U.S. Pat. No. 4,750,800, entitled "Low Stress Mounting of Integrated Optic Chips", by J. T. Fournier et al. and in U.S. Pat. No. 4,871,226, entitled "Mounting of Optical Fibers to Integrated Optical Chips", by D. P. Courtney et al. as well as other devices wherein the conditions of surfaces of the microfabricated device are crucial to device performance. The above-noted patents and patent applications are hereby incorporated herein by reference.
Such devices are manufactured by well-known photolithographic techniques and often have the property that they are no longer functional or operable if heated above a Curie temperature or a melting temperature of one or more constituent portions. As such, these devices often cannot be subjected to the temperature extremes required in order to provide a hermetic seal, for example by welding.
Conventional packaging techniques for such devices (e.g., seam welding of metallic lids to flat packages or flatpacks) often require labor-intensive manual procedures which do not lend themselves to automated production techniques. It has been especially uneconomical and impractical to provide automated mass production techniques for localized heating to the seal area itself without heating the package and the device contained therein.
What are needed are methods and apparatus for providing sealed packages for microfabricated components which packages can be sealed en masse and which do not require heating of the entire microfabricated device and package to the temperatures required in order to form a seal. A further need is for packages which can be repeatedly sealed and unsealed without exposing the components contained therein to temperature extremes.